Control circuits for induction motors



Dec. 29, A, J CONTROL CIRCUITS FORJ'NDUCT i ION MOTORS 3 Sheets-Sheet 1 Filed Jan. 15, 1952 @558 53m at m2 to to to is w 22 w 95% =3 w N F Efim J QNQK Q 9.9M QMQWOMQQ m @558 r 5% km F ti l mm mm m! 363* $3 J 3% ma NNYPNMX l Mal 5% RN [ENHI INVENTOR. Alexander J. Lewus Aim Dec. 29, 1953 w s CONTROL CIRCUITS FOR INDUCTION MOTORS 3 Sheets-Sheet 2 Filed Jan. 15, 1952 MWQMP E k0 hub 29! 6 am onovomowfio 9owomovomo mmmmmmq 7 8m EN INVENTOR. Alexander J. Lewus MEY- Patented Dec. 29, 1953 UNITED STATES PATENT OFFICE CONTROL CIRCUITS FOR INDUCTION MOTORS The present invention relates to control circuits for induction motors and more particularly to starting-running-braking circuits for such motors of the capacitor type.

It is the general objecu of the present invention to provide in a circuit of the character noted a circuit controller that is selectively operative between an off position and forward and reverse positions for the purpose of selectively starting and running the rotor of the associated induction motor in the respective forward and reverse directions, wherein the controller is arranged not only to disconnect the windings of the motor from the associated source of power supply when it is returned from either its forward position or its reverse position back into its ofi position, but also to complete a dynamic braking circuit for the rotor.

Another object of the invention is to provide a circuit controller in a circuit of the character noted, wherein the controller is arranged to em ploy an associated capacitor both for selective starting of the rotor of the motor in the opposite directions, but also for dynamic braking of the rotor when the controller is returned back into its off position.

A further object of the invention is to provide a circuit controller in a circuit of the character noted, wherein the controller is provided with an off position and final forward and reverse po siticns disposed on opposite sides of the off position and intermediate forward and reverse positions respectively disposed between the oii position and the final forward and reverse positions, and wherein the controller effects dynamic braking of the motor in the off position and in the intermediate forward and reverse po sitions in order positively to insure that the rotor is stopped instantly and reversed instantly when the controller is quickly operated from one of its final positions to the other of its final positions.

A still further object of the invention is to provide a circuit controller for starting and run-- ning and braking the reversible rotor of an induction motor of the single-phase split-phase type, including a stator provided with angularly displaced main and auxiliary windings, wherein the auxiliary winding and an associated capacitor are employed for starting the rotor in either direction and for braking the rotor when the controller is returned from either its forward position or its reverse position back into its on position.

Further features of the invention pertain to the particular connection and arrangement of the elements of the electric motor and of the circuit controller, whereby the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by re erence to the following specification taken in connection with the accompanying drawings, in which Figure 1 is a diagrammatic illustration of a starting-running-braking circuit for a single-phase split-phase induction motor of the capacitor type, and including a circuit controller, and embodying the present invention; Fig. 2 is a diagrammatic illustration of a modified form of the circuit; and Fig. 3 is a diagrammatic illustration of another modified form of the circuit.

Referring now to Fig. l of the drawings, there is iilustrated a starting-runningbraking circuit embodying the features of the present invention and comprising an electric motor 9 3 of the single-phase split-phase induction type inciuding a stator IiiI provided with angularly displace; main and auxiliary windings Sci and 1&3 and reversible rotor 64 provided with a squirrelcage winding I85. The rotor It-i is mounted upon an associated shaft, not shown, to which there is operatively connected a centrifugal switch I08 provided with a bridging member I controlling associated contacts see and 538. The centrifugal switch 1'65 is responsive to rotation of the rotor I04 in either direction at a speed somewhat in excess of of the synchrono' speed thereof to move the bridging member into open circuit position with respect to the contacts Hit and H39, and is responsive to rota tion of the rotor I64 in either direction at a speed considerably less than 75% of the syn-- chronous speed thereof to move the bridging member I0? back into its normal closed circuit position with respect to the contacts I52; and I55.

Further the circuit comprises a source of single-phase alternating current supply that may be of volts, a capacitor I Hi and a circuit controller I23 that may be of any conventional type. Specifically the controller :26 may prise supporting structure, not shown, rotata'oiy mounting a drum IZfia (illustrated in relation) and having an off position and icriv rd. and reverse positions as indicated. The support ing structure carries seven stationary cont cts Hi to I21, inclusive, that are operatively assv ciated with the individual contacts in three sets carried by the rotatable drum Iitc. Specifically the rotatable drum iZGc carries a set or" off co 2." tacts, including the individual contacts Iiii, i I34, I35, I36 and IE7, respectively cooperati with the stationary contacts IQI, I22, I2 I26 and I27; a set of forward contacts 2. I 37, inclusive, respectively cooperating with the stationary contacts IZI to I27, inclusive; and a set of reverse contacts I5i to I57, inclusive, re spectively cooperating with the stationary contacts I2! to 12?, inclusive.

In the circuit, the upper line conductor of the source of power supply is connected commonly to the stationary contact I2I and to one terminal of the main winding I02; while the lower line conductor of the source of power supply is connected to the stationary contact I23. The other terminal of the main winding I02 is commonly connected to the switch contact I08 and to the stationary contacts I26 and I21; while the other switch contact I09 is connected to the stationary contact I25. One terminal of the auxiliary winding I03 is connected to the stationary contact I22 and the other terminal thereof is connected to one terminal of the capacitor III), the other terminal of the capacitor I I being connected to the stationary contact I24. The drum contacts I3I, I32, I35, I35, I35, and I3! are commonly connected together; the drum contacts III and its are connected together; the drum contacts I52, I 45 and I45 are commonly connected together; the drum contacts I43 and I4] are connected together; the drum contacts II and I52 are connected together; the drum contacts I53 and I5! are connected together; and the drum contacts I54, I55 and I55 are commonly connected together.

The spread of the drum off contacts I3I, I 35, I36 and I31 is from 0 at the off and stop position approximately on either side thereof in the forward and reverse directions; and the spread of the drum 01f contacts I32 and I34 is from 0 at the off and stop position approximately 30 on either side thereof in the forward and reverse directions. The drum forward contacts I lI, I42 and IM have a spread in the forward direction from about 35 to 60; the drum forward contacts M3, I45 and Id! have a spread in the forward direction from about to 60; while the drum forward contact I46 has a spread in the forward direction from about 25 to 45. Similarly the drum reverse contacts I5I, I52 and I5 3 have a spread in the reverse direction from about 35 to 60; the drum reverse contacts I53, I55 and I5? have a spread in the reverse direction from about 25 to 50; while the drum reverse contact I55 has a spread in the reverse direction from about 25 to 45.

Considering now the operation of the motor I50, when the controller I20 occupies its off position, the main and auxiliary windings I52 and I03 are deenergized, and the main winding I52 is short-circui'ted, and the auxiliary winding I03 and the capacitor I III are shorted in series relation. When the drum IZIIa is rotated in the forward direction (to the right in Fig. l) somewhat in excess of 20, the short-circuit across the main winding I02 is interrupted; and when the drum I2I3a is rotated further in the forward direction 25, the main winding I02 is energized. More particularly, the main winding I02 is connected via the stationary contacts I27 and I23 and the drum contacts is? and H33 directly across the line conductors of the source of power supply. When the drum I20c is rotated further in the forward direction the short across the auxiliary winding I03 and the capacitor III] in series relation is interrupted; and when the drum 120a is rotated further in the forward direction the auxiliary winding I53 is energized. Specifically, one terminal of the auxiliary winding I53 is connected via the stationary contact I22, the drum contacts I42, I and m5, the stationary contacts I25 and I2'I, the drum contacts HI? and I43, and the stationary contact I23 to the lower line conductor of the source of power supply; while one terminal of the capacitor III) is con-- nected via the stationary contacts I25 and I2! and the drum contacts is and III to the upper line conductor of the source of power supply. Accordingly, the main and auxiliary windings I52 and I03 are energized, the auxiliary winding I03 and the capacitor I It being poled in the forward direction with respect to the main winding I52; whereby the rotating fields in the stator IQI effect induction in the squirrel-cage winding I55 so that the rotor I04 is started in the forward direction.

As the drum I20a is rotated still further in the forward direction somewhat in excess of 45, the drum contact I IB disengages the stationary contact I25 encircuiting the centrifugal switch I55. Accordingly, at this time, the lower line conductor of the source of power supply is connected via the stationary contact I23, the drum contacts Hi3 and i 31, the stationary contact I27, the switch contacts I55 and I05, the bridging member I07, the stationary contact I25, the drum contacts I55 and I52, and the stationary contact I22 to one terminal of the auxiliary winding I53. Accordingly, when the rotor I55 is accelerated in the forward direction to a speed somewhat in excess of of the synchronous speed thereof, the centrifugal switch I05 operates the bridging member IIBTI into its open position with res ect to the switch contacts I55 and I05, so as to effect deenergization of the auxiliary winding I53 and the capacitor I It in series relation. At this time, the rotor I04 is accelerated on into its forward running speed, slightly below the synchronous speed by the slip speed, as a result of the energization of the main winding I02; and the rotor I5 3 is operated at the running speed in the forward direction entirely by the energization of' the main winding I52.

tor I55, the drum I20a is returned back into its off position. When the drum IZta is rotated back into its 45 forward position, the drum contact hit again engages the stationary contact I25 for the purpose of short-circuiting the switch contacts I05 and I59, whereby the auxiliary winding I03 and the capacitor III are again energized over the initial circuit previously traced. Thereafter when the drum I200: is returned back toward its on position somewhat 'less than its 35 forward position, the drum contacts I II, etc., disengage the stationary contacts I2I, etc., so that the auxiliary winding I53 is deenergized. Further when the drum IZIia is rotated bacl; toward its off position from its 30 forward position on into its 0 position, the drum contacts I32 and I34 engage the stationary contacts I22 and I25 completing the previously traced short across the auxiliary winding I03 and the capacitor IIB in series relation; and until the drum IZta is returned back toward its off position somewhat less than its 25 forward position, the main winding I02 is energized, whereby the forward rotation of the rotor I5 3 is instantly dynamically braked causing the rotor I05 instantly to assume its rest position. At somewhat less than the 25 forward position of the drum Iita, the drum contacts I55 and It? disengage the stationary contacts I25 and I2? interrupting the circuit for energizing the main winding I52. Finally, when the drum Iziia is returned into its 20 forward position, the short-circuit across the main winding I52 is completed further to insure that the rotor I05 occupies its rest position.

When the drum I2Ila is rotated from its off position in the reverse direction (to the left in Fig. l) somewhat in excess of the short-cincuit across the main winding I02 is interrupted; and when the drum I 20a. is rotated further in the reverse direction the main winding I02 is energized. More particularly, the main winding M32 is connected via the stationary contacts l2? I and the drum contacts I51 and I53 directly across the line conductors of the source of power supply. When the drum I20a is rotated further in the reverse direction the short across the auxiliary winding I03 and the capacitor I I 5 in series relation is interrupted; and when the drum l2da is rotated further in the reverse direction the auxiliary winding m3 is energized. Specifically, one terminal of the auxiliary winding tilt is connected via the stationary contacts I22 and I2! and the drum contacts I52 and I5I to the upper line conductor of the source of power supply; while one terminal of the capacitor lid is connected via the stationary contacts I26, the drum contacts I55, I55 and I55, the stationary contacts I26 and I27, the drum contacts i5? and I53 and the stationary contact I23 to the lower line conductor of the source of power supply. Accordingly, the main and auxiliary windings m2 and I03 are energized, the auxiliary winding I 33 and the capacitor IIfl being poled in the reverse direction with respect to the main winding I82; whereby the rotating fields in the stator Iii! effect induction in the squirrel-cage winding I 05 so that the rotor I04 is started in the reverse direction.

As the drum IZta is rotated still further in the reverse direction somewhat in excess of 45, the drum contact I50 disengages the stationary contact I26, encircuiting the centrifugal switch I05. Accordingly, at this time, the lower line conductor of the source of power supply is connected via the stationary contact I23, the drum contacts I53 and I57, the stationary contact I21, the switch contacts I08 and I09, the bridging member IN, the stationary contact I25, the drum contacts I55 and I54, and the stationary contact We to one terminal of the capacitor I I 0. Accordingly, when the rotor I04 is accelerated in the reverse direction to a speed somewhat in excess or" 75% of the synchronous speed thereof, the centrifugal switch I06 operates the bridging member I 07 into its open positionwith respect to the switch contacts I08 and I 09, so as to effect deenergization of the auxiliary winding I03 and the capacitor I I0 in series relation. At this time, the rotor I04 is accelerated on into its normal reverse running speed, slightly below the synchronous speed by the slip speed, as a result of the energization of the main winding I02; and the rotor ass is operated at the running speed in the reverse direction entirely by the energization of the main winding I02.

In order to arrest reverse rotation of the rotor It; the drum I Zea is returned back into its off position. When the drum I 20a is rotated back into its 45 reverse position, the drum contact I56 again engages the stationary contact I26 for the purpose of short-circuiting the switch contacts I 533 and W9, whereby the auxiliary winding I03 and the capacitor II are again energized over the initial circuit previously traced. Thereafter when the drum IZda is returned back toward its off position somewhat less than its 35 reverse position, the drum contacts I5I, etc., disengage the stationary contacts I2I, etc., so that the auxiliary winding I03 is deenergized. Further, when the drum 201! is rotated back toward its of? position from its 30 reverse position on into its, 0 position, the drum contacts I32 and I34 engage the stationary contacts I22 and I24 completing the previously traced short across the auxiliary winding I03 and the capacitor H0 in series relation; and until the drum I200. is returned back toward its ofi position somewhat less than its 25 reverse position, the main winding I02 is energized; whereby the reverse rotation of the rotor I04 is instantly dynamically braked causing the rotor I 04 instantly to assume its rest position. At somewhat less than the 25 reverse position of the drum I20a, the drum contacts I56 and I 57 disengage the stationary contacts I26 and I2? interrupting the circuit for energizing the main winding I92. Finally, when the drum mm is returned into its 20 reverse position, the short-circuit across the main winding I02 is completed further to insure that the rotor its occupies its rest position.

In view of the foregoing, it will be appreciated that since the rotor its is instantly dynamically braked when the drum lien; is operated from either its forward position or its reverse position back into its off position, and since the centrifugal switch m6 is lay-passed in the 25-45 forward position and in the 25-45 reverse position of the drum I25a, the drum I Eda may be quickly operated from either of its extreme positions into the other of its extreme positions with the absolute assurance that the direction of rotation of the rotor loll will be instantly reversed.

In passing, it is noted that the drum IEIla is norm-2"ly biased by means, 1: t shown, into its oii position may be restrained by means, not shown, each of its forward and reverse positions in an obvious manner.

Referring now to 2 of the drawings, there is illustrated a modified "form of the starting rLmning-braking circuit embodying the features of the present invention and comprising an electric motor 253!) of tie single-phase split-phaseinjunction type inc .ding stator ZQI provided with angularly displaced main and auxiliary windings 252 and 283 and a reversible rotor s provided with a squirrel-cage winding rotor 22:2 is inou not shown, to nected a centrildga bridging memb tacts 228 and s42. The cen fugal switch 253 is responsive to rotation of rotor 28-? in either direction at a speed somewhat in ex s of 15% associated conof the synchronous speed thereof to move the bridging member 2t? into n circuit position with respect to the contacts and is responsive to rotation of the rotor 2 2s in either direction at a speed considerably less than of the synchronous speed thereof to move the bridging member back into its normal closed circuit position with respect to the contacts and 26%.

Further, the ci it comprises a single phase alternatrlg current supply that may be of volts, a capacitor and a ci cuit controller 22s that may be of any conventional ty Specificall the controller comp supporting structure, not shown, mounting a drum (illustrated relation) and having "ition an and reve'se positions as indicated. porting structure carries s tacts 225 to 22?, inclusive, that are operatively associated with the individual contact" in three sets carried by the rotat e drum 228a. Specifically, the rotatable crr. carries set oft source of rotatably contacts, including the individual contacts 232 and 235, respectively cooperating with the sta tionary contacts 222 and 225; a set of forward contacts 254 and 253, inclusive, respectively cooperating with the stationary contacts 22! to 22?, inclusive; and a set of reverse contacts 25! to 25's, inclusive, respectively cooperating with the stationary contacts 22! to 22?, inclusive. Also the controller 222 comprises a single-pole single-throw snap-acting switch 269 that is preferably of the toggle-action type, including a pair of hinged togglearms 25! mounted upon blocks 2%2 carried by the supporting structure, not shown, as well as a toggle set and trip member 253, a contact bridging member 264 and a pair of switch contacts and 253. Further the drum 22% carries an off setting member 2', a forward setting member 212, and a reverse setting member 2T5 cooperating with the member 253, the off setting member 2H has a spread from at the off and stop position approximately on either side thereof in the forward and reverse directions. The forward setting member 232 has a spread in the forward direction from about 50 to 60, while the reverse setting member 213 has a spread in the reverse direction from about 56 to 60.

in the circuit, the line conductors of the source of supply are respectively connected to the stationary contacts 22! and 223. One terminal of the main winding 2&2 is connected to the stationary contact 22 1 and the other terminal of the main winding 232 is commonly connected to the switch contact 2:353, to the stationary contact 22! and to the switch contact 2&5; the other switch a contact 2539 is commonly connected to the stationary contact 225 and to the switch contact 2 36. One terminal of the auxiliary winding 253 is connected to the stationary contact 222 and the other terminal thereof is connected to one terminal of the capacitor 2H3, the other terminal of the capacitor 2 it being connected to the stationary contact 225. The drum contacts 232 and 235 are connected together; the drum contacts Edi, 2&2 and are commonly connected together; the drum contacts 2&3 and 24? are connected together; the drum contacts 2&5 and 255 are connected together; the drum contacts 25!, 25s and 255 are commonly connected together; the drum contacts 252 and are connected together; and the drum contacts 253 and 25'! are connected together.

The spread of the drum oif contacts 232, etc, is from 6 at the off and stop position approximately on either side thereof in the forward and reverse directions. The drum ofi contacts 232, etc, are separated from the drum forward contacts -5, etc., by approximately 5 in the forward direction, and separated from the drum reverse contacts 255, etc, by approximately 5 in the reverse direction. Further the drum forward contacts 2M, etc, have a spread in the forward direction from ahout 25 to 60. Similarly the drum reverse contacts 25%, etc., have a spread in the reverse direction from about 25 to 66".

Considering now the operation of the motor 2%, when the controller 229 occupies its off position, the main and auxiliary windings 202 and 2% are deenergized, the snap switch 260 occupies its closed position, and the auxiliary winding 233 and the capacitor 2H) are shorted in series relation. When the drum 22% is rotated in the forward direction (to the right in Fig. 2) somewhat in excess of 20, the short across the auxiliary winding 2833 and the capacitor 2H3 in series relation is interrupted; and when the drum 220a is rotated further in the forward direction 25, the starting circuits for the motor 282 are completed. More particularly, the main winding 202 is con nected via the stationary contacts 225 and 22! and the drum contacts 24 and 24! and the sta tionary contacts 22'! and 223 and the drum contacts 2M and 2133 directly across the line conductors of the source of power supply. One terminal of the auxiliary Winding 293 is connected via the stationary contact 222, the drum contacts 252 and 2d! and the stationary contact 22! to the upper line conductor of the source of power supply; while one terminal of the capacitor 2H3 is connected via the stationary contact 225, the drum contacts 2&5 and 2 36, the stationary contact 228, the switch contacts 256 and 265, the bridging member 26d, the stationary contact 221, the drum contacts 24! and 2G3 and the stationary contact 223 to the lower line conductor of the source of power supply. Accordingly, the main and auxiliary windings 262 and 2&3 are energized, the auxiliary winding 293 and the capacitor 2W being poled in the forward direction with respect to the main winding 202 whereby the rotating fields in the stator 29! effect induction in the squirrelcage winding 2&5 so that the rotor 2% is started in the forward direction.

As the drum 226a is rotated still further in the forward direction the member 2i2 engages the member 263 operating the snap switch 26%) into its open position, encircuiting the centrifugal switch 286. Accordingly, at this time, the lower line conductor of the source of power supply is connected via the stationary contact 223, the drum contacts ass and 24?, the stationary contact 22?, the switch contacts 288 and 269, the bridging member 291, the stationary contact 22 E, the drum contacts 245 and 245, and the stationary contact 225 to one terminal of the capacitor 2w. Accordingly, when the rotor 20s is accelerated in the forward direction to a speed somewhat in excess of 75% of the synchronous speed thereof, the centrifugal switch 285 operates the bridging member 20'! into its open position with respect to the switch contacts 288 and 269 so as to effect deenergization of the auxiliary winding 2&3 and the capacitor Zlii in series relation. At this time, the rotor 264 is accelerated on into its forward running speed, slightly below the synchronous speed by the slip speed, as a result of the energization of the main winding 2G2; and the rotor 28% is operated at the running speed in the forward direction entirely by the energization of the main winding 202.

In order to arrest forward rotation of the rotor 2%, the drum 220a is returned back into its off position. When the drum 22cc is rotated back toward its off position somewhat less than its 25 forward position, the drum contacts 2, etc., disengage the stationary contacts 22!, etc., so that the main and auxiliary windings 202 and 203 are deenergized. Further when the drum 226a is rotated back toward its off position from its 20 1 forward position on into its 6 position, the drum contacts 232 and 235 engage the stationary contacts 222 and 225 respectively completing the previously traced short across the auxiliary winding 2G3 and the capacitor 2H3 in series relation. Finally when the drum 226a is rotated back into its 10 forward position, the member 21! engages the member 263 operating the snap switch 259 back into its closed position. At this time,-the rotor 204 is still rotating in the forward direction, whereby the residual magnetism in the stator 20! causes the squirrel-cage winding 205 to induce a voltage in the auxiliary winding 203, whereby current circulates therefrom through the capacitor file in series relation producing an additional magnetic flux that reacts with the squirrebcage winding 2%, whereby the reaction tends to rotate the rotor 22% in the reverse direction so that rota tion of the rotor in the forward direction is quickly dynamically braked causing the rotor quickly to assume its rest position.

When the drum 228a is rotated from its on position in the reverse direction (to the left in Fig. 2) somewhat in excess of the short across the auxiliary winding 2% and the capacitor Ziil in series relation is interrupted; and when th drur 22% is rotated further in the reverse direction 25" the starting circuits for the are cornpleted. More particularly, the main winding ilt. is connected via the stationary contactsfii l and $221, the drum contacts and 25!, the stationary contacts 22? and the drum contacts 25? and 253 directly across the line conductors of the source of power supply. One terminal of the auxiliary winding 2&3 is connected via the stationary contact 222, the drum contacts 252 and 258, the stationary contact 225, the switch. con tacts 255i and 255, the bridging member 25 3, the stationary contact 22?, the drum contacts 25? and 253 and the stationary contact 22-? to the lower line conductor of the source of power supply; while one terminal of the capacitor 255) is connected via the stationary contact 225, the drum contacts 255 and lei and the stationary contact 225 to the upper line conductor of the source of power supply. Accordingly, the main and auxiliary windings 282 and 2&3 are energized, the aux-- iliary winding 2&3 and the capacitor 113 being poled in the reverse direction with respect to the main winding 2%2 whereby the rotating fields in the stator 2M effect induction in the squirrel-cage winding 285 so that the rotor 2M started in the reverse direction.

As the drum is rotated still further in the reverse direction the member engages the meinbc 253 operating the snap switch see into its open position, encircuiting the centrifugal switch Accordingly, at thistinie the lower line conductor of the source oi power supply is connected via the stationary contact 223, the drum contacts and 25?, the stationary contact the switch contacts 258 the bridging member ill, tr e stationary contact 223, the dr .121 cts and and the stationary contact inal of th au: liary winding 2E3. Accordingly, vthen the rotor is accelerated the reverse direction to a speed s' inewhat e cess of of the synchronous speed therecentriiugal teloperates the bridg ng oer into its open position with respect to switch contacts and Edd so as to effect energization of the auxiliary winding and capacitor 2 it} in series relation. At this time, the rotor is accelerated on into its reverse running speed, slightly below the synchronous speed by the slip as a result {31 the energization of the main winding the rotor operated at the run g speed in the reverse direction entirely by the energization of the main winding Edit.

In order to arrest reverse rotation the rotor the drum Etta is returned back into position. When the rctat d bacl: toward. its on position somewhat less than its reverse position, the drum contacts Eel, etc, disengage the stationary contacts 221, etc, so that 10 the main and auxiliary windings 202 and 293 are deenergized.

Further when the drum 226a is rotated back toward its on position from its 20 reverse position, on into its 0 position, the drum contacts 232 and 235 engage the stationary contacts 222 and 225 respectively completing t previously traced short across the auxiliary winding 293 and the capacitor 2 l '3 in series relation. Finally when the drum 220a is rotated bacl; into its reverse position, the member 2?! engages the member operating the snap switch 25% back into its closed position. At this time, the rotor 29-3 is still rotating in the reverse direction, whereby the residual magnetism in the stator Elli causes the squirrel-cage winding 2&5 to induce a voltage in the auxiliary winding 263, whereby current airculates therefrom through the capacitor Zil in series relation producing an additional magnetic flux that reacts with the squirrel-cage winding 252i, whereby the reaction tends to rotate the rotor in the forward direction. so that rotation of the rotor 20:3 in the reverse direction is quickly dynamically braked causing the rotor quickly to assume its rest position.

In view of the foregoing, it will be appreciate: that since the rotor 206 is dynamically braked when the drum 228a is operated from either its forward position or its reverse position back into 'ts off position, and sin e the centrifugal switch 36 is by-passed by the snap switch rec in the .-.G forward-10 reverse positions of the drum 22%, the drum 22% may be quickly operated from either of its extreme positions into the other of its extreme positions with the absolute assurance that the direction of rotation of the rotor 2% will be instantly reversed.

In passing, it is noted that drum 223:: is normally biased by means, not shown, into its on position and may be restrained by means, not shown, in each of its forward and reverse positions, in an obvious manner.

Referring now to Fig. 3 of the drawings, there is illustrated another modified form of the starting-runningbraking circuit embodying the features of the present invention and comprising an electric motor 390 of the single split-phase induction type including a stator 3% provided with angularly dis laced main and auxiliary windings 3132 and 393 and a reversible rotor 365 provided with a squirrel-cage winding Associated with the motor 369 is a relay 386 that is provided with a winding e'lli'i and pair of contacts 3.08. The relay 395 is so constructed arranged that when a heavy current correspond ing to a starting condition or" the motor traverses the winding 393-, the contacts are closed, and when a line current corresponding to a running condition of the motor traverses the winding 30?, the contacts 398 are opened; the contacts 393 normally occupying their open position.

Further the circuit comprises a source of singlephase alternating current supply that he or" -volts, a capacitor and a circuit con-trolls are that may be of any conventional type. Specifically the control 329 supporting structure, not shown, rotatably mounting a drum iiziia (illustrated in iiatwise relation) and having an position, and forward and reverse positions as indicted. The supporting structure carries sir: stationary contacts to inclusive, that are operatively associated with the individual contacts in three sets carried by the rotatable drum 1i Specifically the rotatable drum site canries a set of off contacts, including the individual contacts 332 and 33 respectively cooperating with the stationary contacts 322 and 32s; a set of forward contacts to see, inclusive, respectively cooperating with the stationary contacts 32E to are. inclusive; and a set of reverse contacts sci to 35%, inclusive, respectively cooperating with the stationary contacts 32! to 32s, inclusive. In the circuit, the upper line conductor of the source of power supply is connected commonly to the stationary contact 32l and to one terminal of the main winding 3B2; while the lower line conductor of the source of power supply is connected to the stationary contact 323. The otherterminal of the main winding as: is con= nected to one terminal of the relay winding 36?; while the other terminal of the relay winding 3t? is commonly connected to one of the relay contacts of the pair 3G8 and to the stationary p contact 32, the other relay contact of the pair sec being connected to the stationary contact 525. One terminal of the auxiliary winding see is connected to the stationary contact 325 and the other terminal thereof is connected to one terminal of the capacitor sit, the other terminal of the capacitor Sid being connected to the stationary contact 322.

The drum contacts 332 and 33d are connected together; the drum contacts 3 5i and 3623 are connected together, the drum contacts 3% and 3 35 are connected together, the drum contacts and 345 are connected together, the drum contacts 355i and 352 are connected together; the drum contacts 353 and 356 are connected together, and the drum contacts 35 and are connected together. The spread of the drum off contacts 332, etc, is from at the off and stop position approximately 30 on either side thereof in the forward and reverse directions. The drum forward contacts 36!, 3'32, 3% and 345 have a spread in the forward direction from about 35 to 60; while the drum forward contacts 3% and 346 have a spread in the forward direction from about 25 to 60. Similarly, the drum reverse contacts 35!, 352, 35 i and 355 have a spread in the reverse direction from about 35 to 60; While the drum reverse contacts 353 and 356 have a spread in the reverse direction from about to 60".

Considering now the operation of the motor 3%, when the controller 329 occupies its ofi position, the main and auxiliary windings 302 and 393 are deenergized, and the auxiliary winding 3% and the capacitor 3H} are shorted in series relation. When the drum 32% is rotated in the forward direction (to the right in Fig. 3) 25, the main winding 362 and the relay winding 3c! are energized in series relation via a circuit, including the stationary contact 32%, the drum contacts 3 38 and 3 53, and the stationary contact 323, whereby the heavy current traversing the main winding 352 and the relay winding Sill efiects operation of the relay contacts 398 into closed position. When the drum 320a is rotated further in the forward direction somewhat in excess of the short across the auxiliary winding 39% and the capacitor 356 in series relation is interrupted; and when the drum 328a is rotated still further in the forward direction the starting circuit for the auxiliary winding 39-3 is completed. More particularly, one terminal of the auxiliary winding 3GB is connected via the stationary contact 324, the drum contacts 364 and 3M, and the stationary contact 325 to the upper line conductor of the source of power supply; while one terminal of the capacitor Sic is connected via the stationary contact 322, the drum contacts and the stationary contact 322%, the relay contacts tilt, the stationary contact 326, the drum contacts 3% and 3 53, and the stationary contact 323 to the lower line conductor of the source of power supply. Accordingly, the main and auxiliary windings and 333 are energized, the auxiliary winding 3133 and the capacitor Bic being poled in the forward direction with respect to the main winding d232, whereby the rotating fields in the stator till eficct induction in the squirrel-cage winding so that the rotor tits is started in the forward direction.

When the rotor is accelerated in the forward direction somewhat below the forward run-- ning speed, slightly below the synchronous speed by the slip speed, thecurrent traversing the main winding 332 and the relay winding it}? is substantially reduced, whereby the relay contacts Silt are opened to deenergize the aux iary winding 3&3 and the capacitor see in scnss relation. At this time, the rotor is accelerated on into its forward running speed as a result of the energization of the main winding 382; and the rotor tilt is operated at the running speed in the for ward direction entirely by the energization of the main winding 3&2.

In order to arrest forward rotation of the rotor 355 3, the drum 32% is returned back into its off position. When the drum Etta is rotated back toward its off position somewhat les than its 35 forward position, the drum contacts 365, 3M and 3&5 disengage the respective stationary contacts 32!, 322, 32% and 325 in order to insure deenergization of the auxiliary winding the capacitor 31s in series relation; and when the drum site is rotated bacl: into its to forward position, the drum contacts and reengage the stationary contacts 322 and 32:3 in orrler'to complete the path for shorting the auxiliary winding 303 and the capacitor sic in series relation. At this time, the main winding 392 is energized in series relation with the relay winding while the auxiliary winding ass and the capacitor 3H3 are shorted in series relation, whereby iorward rotation of the rotor ass is immediately arrested to reduce the coupling between the main and auxiliary windings 392 and set. However the main winding 3&2 and the relay winding til? are not damaged by undue heating since the drum $2M in its return back toward its off position in=- terrupts in its 25 forward position the circuit for energizing in series relation the main winding 302 and the relay winding till.

When the drum 329a is rotated from its oil position in the reverse direction (to the left in Fig. 3) 25, the main winding 3&2 and the relay winding Sill are energized in series relation via a circuit including the stationary contact 325, the drum contacts 353 and 353 and the stationary contact 323, whereby the heavy current traverw ing the main winding can and the relay winding 39'! effects operation of the relay contacts 393 into closed position. When the drum 325a is rotated further in the reverse direction somewhat in excess of 30 the short across the auxiliary winding 3533 and the capacitor 355 in series relation is interrupted; and when the drum 329a is rotated still further in the reverse direction 35 the starting circuit for the auxiliary winding 383 is completed. More particularly, one terminal of the capacitor 3i!) is connected via the stationary contact 322, the drum contacts 352 and 35! and the stationary contact 32! to the upper line conductor of the source of power supply; while one terminal of the auxiliary windhis 393 is connected via the stationary contact 324, the drum contacts 35d and 355, the stationany contact the relay contacts 383, the stationary contact 325, the drum contacts 355 and 353, and the stationary contact 323 to the lower line conductor of the source of power supply. Accordingly, the main and auxiliary windings E392 and 3% are energized, the auxiliary winding 3G3 and the capacitor Sill being poled in the reverse direction with respect to the main winding 3H2, whereby the rotating fields in the stator 39! effect induction in the squirel-cage winding 38% so that the rotor 364 is started in the reverse direction.

When the rotor set accelerated in the reverse direction somewhat helow the forward running speed, slightly below the synchronous speed by the slip speed, the current traversing the main winding 3st and the relay winding St! is substantially reduced, whereby the relay contacts 3% are opened to deenergize the auxiliary winding 3G3 and. the capacitor 356 in series relation. At this time, the rotor is accelerated on into its reverse running speed as a result of the energization of the main winding 3252; and the rotor 364 is operated at the running speed in the reverse directly entirely by the energization of the main winding 332.

In order to arrest reverse rotation of the rotor St t, the drum 32lla is returned back into its oil position. When the drum 328a is rotated back toward its ofi position somewhat less than its 35 reverse position, the drum contacts 35!, 3'52, 35% and 355 disengage the respective stationary contacts 323i, 322, 32s and 325 in order to insure deenergization of the auxiliary winding 393 and the capacitor 3 l 0 in series relation; and when the drum 32 to, is rotated back into its 30 reverse position, the drum contacts 332 and 334 reengage the stationary contacts are and in order to complete the path for shorting the auxiliary winding 333 and the capacitor 3H} in series relation. At this time, the main winding 332 is an ergized in series relation with the relay winding 38? while the auxiliary winding and the capacitor til i; are shorted in series relation, whereby the forward rotation of the rotor this is immediately arrested to r duce the coupling hetween the main and auxiliary windings 382 and 3523. However the main winding 3%2 and the relay winding 3e? are not damaged by undue heating since the drum 322a in its return back toward its on position interrupts in its 25 reverse position, the circuit for energizing in series relation the main winding and the relay winding 35?.

In view of the foregoing, it will be anpr elated that since the rotor 3&4 is dynamically braked when the drum 326d is operated either from its forward position or its reverse position ba k into its oh position, the drum 323a may be quickly operated from either of its extreme positions into the other of its extreme positions with the ab solute assurance that the direction of rotation of the rotor will be instantly reversed.

In passing, it is noted that the drum 329a is normally biased by means, not shown, into its off position may be restrained by means, not shown, in each of its forward and reverse positions in an obvious manner.

In view of the foregoing, it is apparent that there has been provided improved starting-runhing-braking circuits for induction motors of the single-phase split-phase or capacitor type that insure ready starting and running of the motors in either direction and positive reversal of ti c direction of rotation of the motors incident to operation of the associated circuit controllers between their extreme positions, which arrangements employ the same capacitors for starting and for instantly dynamically braking purposes.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will he understood that various modifications may he made therein, and it is intended to cover in the appended claims all such modifications that fall within the true spirit and scope of the invention.

What is claimed is:

1. In a control circuit including an induction motor provided with a stator havi g angularly displaced main and auxiliary windings and a reversible rotor having a squirrel cage winding, a capacitor, a control switch, means respon ive to astarting condition of said rotor in ei her direc tion for operating said control switch into its closed position, and a source of single phase alternating current supply; the combination coinprising a circuit controller provided with an off position and forward and reverse positions respectively disposed on opposite sides of said off position, insane for selectively operating controller between its diiierent positions, means responsive to operation of said controller from its off position into its forward position for connect said winding to said source a for connecting said. auxiliar winding and said capacitor, and said control switch in series relatio: to said source so that main auxiliary windings are phased to effect forward starting of rotor, means, responsive to a forward running condition of said rotor for operating said control switch into its open position so that forward running of said rotor is effected by said main winding, means responsive to operation of s controller from its oil posi n into its reverse position for Connecting said main win I to sale source and for connecting said at c winding and said capacitor and said control switch in series relation to said source so that said main and auxiliary wit lines are phased to effect reverse starting or" rotor by said main auxiliary windings, mea" s responsive to a re verse running condition of said rotor for op rating said control switch into its open position so that reverse running of said rotor is eiiectec'; by said main winding, means response tion of controller from either other positions back into its o f connecting said auxiliary winning pacitor and said control switch in eerie. relation from source and ray conipl a short across said auxiliary winding are, capacitor in series relation so as to effect nainic braking of said rotor and then for disco nee-ting said main winding from said source, acditicnal means responsive to operation of said controller from its oil" position into either of its other positions' for interrupting said short across said auxiliary winding and said capacitor in series relation.

'2'. In a control circuit including an induction motor provided with a stator-ha ng angularly displaced main and auxiliary v linings and re versible rotor having a squirrei-cage winding, a

capacitor, a control switch, means governed by rotation of said rotor in either direction at a relatively low speed for operating said control switch into its closed position, and a source of single-phase alternating current supply; the combination comprising a circuit controller provided with an oil position and forward and reverse positions respectively disposed on opposite sides of said on position, means for selectively operating said controller between its difierent positions, means responsive to operation of said controller from its off position into its forward position for connecting said main winding to said source and for connecting said auxiliary winding and said capacitor and said control switch in series relation to said source so that said main and auxiliary windings are phased to efiect forward starting of said rotor by said main and auxiliary windings, means governed by forward rotation of said rotor at a relatively high speed for operating said control switch into its open position so that forward running of said rotor is effected by said main winding, means responsive to operation of said controller from its ofi position into its reverse position for connecting said main winding to said source and for connecting said auxiliary winding and said capacitor and said control switch in series relation to said source so that said main and auxiliary windings are phased to eiiect reverse starting of said rotor by said main and auxiliary windings, means governed by reverse rotation of said rotor at a relatively high speed for operating said control switch into its open position so that reverse running of said rotor is eiiected by said main winding, means responsive to operation of said controller from either one of its other positions back into its off position for disconnecting said auxiliary winding and said capacitor and said control switch in series relation from said source and for completing a short across said auxiliary winding and said capacitor in series relation so as to efiect dynamic braking of said rotor and then for disconnecting said main winding form said source, and additional means responsive to operation of said controller from its off position into either of its other positions for interrupting said short across said auxiliary winding and said capacitor in series relation.

3. In a control circuit including an induction motor provided with a stator having angularly displaced main and auxiliary windings and a reversible rotor having a squirrel-cage winding, a capacitor, a control relay provided with a winding and a pair of contacts, said relay contacts normally occupying their open position, said relay winding being responsive to a heavy current traversing it to operate said relay contacts into their closed position, and a source of single-phase a1- ternating current supply; the combination comprising a circuit controller provided with an off position and forward and reverse positions respectively disposed on opposite sides of said on position, means for selectively operating said c0ntroller between its difierent positions, means responsive to operation of said controller from its ofi position into its forward position for connect-.

ing said main winding and said relay winding in series relation to said source and for connecting said auxiliary winding and said capacitor and said relay contacts in series relation to said source so that said main and auxiliary windings are phased to effect forward starting of said rotor by said main and auxiliary windings, said relay winding being responsive to a light current traversing it to return said relay contacts into their open position so that forward running of said rotor is eflooted by said main winding, means responsive to operation of said controller from its oil position into its reverse position for connecting said main winding and said relay winding in series relation to said source and for connecting said auxiliary winding and said capacitor and said relay contacts in series relation to said source so that said main and auxiliary windings are phased to effect reverse starting of said rotor by said main and auxiliary windings, said relay winding being responsive to a light current traversing it to return said relay contacts into their open position so that reverse running of said rotor is effected by said main winding, means responsive to operation of said controller from either one of its other positions back into its off position for disconnecting said auxiliary winding and said capacitor and said relay contacts in series relation from said source and for completing a short across said auxiliary winding and said capacitor in series relation so as to effect dynamic braking of said rotor and then for disconnecting said main winding and said relay winding in series relation from said source, and additional means responsive to operation of said controller from its ofi position into either of its other positions for interrupting said short across said auxiliary winding and said capacitor in series relation.

4. In a control circuit including an induction motor provided with a stator having angularly displaced main and auxiliary windings and a reversible rotor having a squirrel-cage winding, a capacitor, a control switch, means responsive to a starting condition of said rotor in either direction for operating said control switch into its closed position and a source of single phase alternating current supply; the combination comprising a circuit controller provided with an off position and forward and reverse positions respectively disposed on opposite sides of said oil position, means for selectively operating said c0ntroller between its different positions, means responsive to operation of said controller from its off position into its forward position for connecting said main winding to said source and for connecting said auxiliary winding and said capacitor and said control switch in series relation to said source so that said main and auxiliary windings are phased to eiiect for ard starting of said rotor by said main and auxiliary windings, means responsive to a forward running condition of said rotor for operating said control switch into its open position so that forward running or said rotor is efiected by said main winding, means responsive to operation of said controller from its on" position into its reverse position for connecting said ma n winding to sa d source and for con-- necting said auxiliary winding and said capacitor and said control switch in series relation to said source so that said main and auxiliary windings are phased to effect re erse starting of said rotor by said main and auxiliary windings, means responsive to a reverse running condition of said rotor for operating said control switch into its open po ition so that rever e r nning of said rotor is efiected by said main winding, means responsive to operation of said controller from either one of its other positions back into its on position for disconnecting said auxiliary winding and said capacitor and said control switch in se' ries relation from said source and for completing a short across said main winding and across said auxiliary winding and said capacitor in series relation so as to effect dynamic braking of said rotor and then for disconnecting said main 17 winding from said source, and additional means responsive ,to-operation of said controller .from its ofi position into either'of its other positions for interrupting said short across saidmain winding. and across said. auxiliary winding andsaid capacitor in series relation.

.-5.;In a control circuit including an induction motor provided with a stator having angularly displaced main. and auxiliary windings and; areversible rotor'having a.squirrclecagewinding, a capaoitor a control switch,-means responsive to. a startingcondition of said rotor incither direction for operating said control switch into ,its closed position, and a souroeaof ,singie phase alternating currentsupply; the combination comprisingacircuit controller provided with an off position and intermediate forward .and reverse positions respectively disposed onoppositesides of said oif position and final iorwardand reverse positions respectively, disposedadjacent to saidintermediate forward and reverse positions, means for selectively operating said controllerbetween its different positions, meansresponsive to operation ofsaid controller fIOliiiliS oiT position into its in termediate forward position for connecting said main winding tosaid sourceand for connecting said auxiliary winding andsaid capaeitorand said control switch in series relation to said source so that said main andauxiliary windings are phased to eiiect forward starting of said rotor by said main and auxiliary windings, means responsive to operationoisaid controller from its intermediatexforward position into its final forward position forinterrupting, a previously completed-bypass path around said control switcnmeans responsive to a forward-running condition of said rotor for operating said control switch into its open ,position so that forward running of said rotor is effected by said main winding, meansresponsive to operation of saidcontroller from its off position into its intermediate reverseiposition for connecting said main windingto said source and for connecting said auxiliary winding and said capacitor and said control switchinlseries relation to said, source so thatsaid main-and auxiliary windings are phased to, effect reverse starting of saidrotor by said main and auxiliary windings, means iresponsiveto operation of said controller from its intermediate reverse; position into its final reverse position for interrupting said previously coznpleted by-pass path around ,said control switch, means responsive to ,a reverse running condition of. said rotorfor operatingsaid control switch into its open position so that reverse running ofisaid frotor isleffected bysaid main winding, meansresponsive to operation of said controller from either one of its ifinalpositions back into the adjacent one of its intermediate positions for completing said by-pass path around saidcontrol switch, means responsive to operation of said controller from either one of its intermediate positions back into itsoffposit'ion for disconnecting said auxiliary winding and said capacitor and said control switch in series relation from said source and for completing a short across said auxiliary winding and said capacitor in series relation so as to effect dynamic braking'of said rotor and then for disconnecting said main winding from said source, and additional means .responsiveto operation of said controller from its-.oif position into'either of its intermediate positions for interrupting said short across said auxiliary winding and said capacitor in series relation.

1.6, -.In .a controlcircuitincluding an induction 18 motor provided with a stator having angularly displacedmain and auxiliary windings a reversiblerotorhaving a squirrel-cage winding, a capacitor, .a control switch, means responsive to astartingcondition ofisaid rotor in either'directlon for operating said .con ..oi sw tch into its closed position, and a source of single phase alternating current supply; the c ibinationcomprisinga circuit controller provided with an off position and intxrnediate forward and reverse positions, respectively disposed-on opposite sides ofsaid oirxpositionand final forward andreverse positions respectively disposed adjacent to said intermediate forward and reverse positions, means for selectively operating said controller between its different positions, a snap-acting switch arranged in icy-passing relation with said control switchand occupying its closed position when-said controller occupies its off position, means responsive to operation of said controller from its off position intoits intermediate'forwardpositionfor connecting said main winding to said source and for connecting said auxiliary winding and said capacitor and said control switch in series relation to said source sothat said main and auxiliary windings are phased-to effecttforiward starting of said rotor by said main and'auxiliary windings, means responsivetooperation of said controller from its intermediate forward position into its final forward position for operating said snap-switch into its open-position, means responsive to a forward running conditionof said rotor for operating said control switch-into its open position so that forward running ofsaid rotor is effected by-said main winding, meansresponsiveto operation of said controller from its 01f position into its intermediate reverse position for connecting said main winding to said source and for connecting said auxiliary winding and-said capacitor andsaid control switch in series relation to said-source so that said mainand auxiliary windings are phased to effect reverse starting ofsaid rotor by said main andauxiliary windings, .means re'sponsive to operationof said controllerlfrom its intermediate reverse position ,into its. final reverse position for operating said snap-switch into its open position, means responsive we reverse running condition of said rotor for. operatingsaid control switch into its: open position so-thatreverse running of said rotor is eiiected by said main winding, means responsive :to operation of said controller from either one of its final positions back into the adjacentoneof itsiinterinediate positionsfor operating said snap-switch into its closed position, means responsiveto operation of said controller from eitherone or" its intermediate positions back into its off position for disconnecting saidauxiliary winding andsa-id capacitor and said control switch in series relation from said source and for completing ashort'across said auxiliary windingand saidlcapacitor in series relation was to efiect dynamic braking of said rotor and thenior disconnecting said main winding from said source, andiad'ditional means responsive toioperation of said controller froin'its off position into either of its intermediate positionsfor'interruptingsaid short across said auxiliary winding and said capacitor in series relation."

-7. 'In a control circuit esame direction for operating said control switch into its closed position, and a source of single phase alternating current supply; the combination comprising a circuit controller provided with an off position and intermediate forward and reverse positions respectively disposed on opposite sides 7 of said off position and final forward and reverse positions respectively disposed adjacent to said intermediate forward and reverse positions, means for selectively operating said controller betweenits different positions, means responsive to operation of said controller from its 01f position into its intermediate forward position for connecting said main winding to said source and for interrupting a previously completed short across said auxiliary winding and said capacitor in series relation, means responsive to operation of said controller from its intermediate forward position into its final forward position for connecting said auxiliary winding and said capacitor and said control switch in series bridge relation to said source so that said main and auxiliary windings are phased to effect forward starting of said rotor by said main and auxiliary windings, means responsive to a forward running condition of said rotor for operating said control switch into its open position so that forward running of said rotor is effected by said main winding, means responsive to operation of said controller from its off position into its intermediate reverse position for connecting said main winding to said source and for interrupting said previously completed short across said auxiliary winding and said capacitor in series relation, means responsive to operation of, said controller from its intermediate reverse position into its final position for connecting said reverse auxiliary winding and said capacitor and said control switch in series relation to said source so that said main and auxiliary windings are phased to effect reverse starting of said rotor by said main and auxiliary windings, means responsive to a reverse running condition of said rotor for operating said control switch into its open position so that reverse running of said rotor is effected by said main winding, means responsive to operation of said controller from either one of its final positions back into the adjacent one of its intermediate positions for disconnecting said auxiliary winding and said capacitor and said control switch in series relation from said source and for completing said short across said auxiliary winding and said capacitor in series relation so as to effect dynamic braking of said rotor, and means responsive to operation of said controller from either one of its intermediate positions back into its off position for disconnecting said main winding from said source.

8. In a control circuit including an induction motor provided with a stator having angularly displaced main and auxiliary windings and a reversible rotor having a squirrel-cage winding, a capacitor, a control relay provided with a winding and a pair of contacts, said relay contacts normally occupying their open position, said relay winding being responsive to a heavy current traversing it to operate said relay contacts into their closed position,,and a source of single-phase alternating current supply; the combination comprising a circuit controller provided with an off position and intermediate forward and reverse positions respectively disposed on opposite sides of said off position and final forward and reverse positions respectively disposed adjacent to said intermediate forward and reverse positions,

means for selectively operating said controller between its different positions, means responsive to operation of said controller from its off position into its intermediate forward position for connecting said main winding and said relay winding in series relation to said source and for interrupting a previously completed short across said auxiliary winding and said capacitor in series relation, means responsive to operation of said contrdller from its intermediate forward position into its final forward position for connecting said auxiliary winding and said capacitor and said control switch in series relation to said source so that said main and auxiliary windings are phased to effect forward starting of said rotor by said main and auxiliary windings, said relay winding being responsive to a light current traversing it to return said relay contacts into their open position so that forward running of said rotor is effected by said main winding, means responsive to operation of said controller from its off position into its intermediate reverse position for connecting said main winding to said source and for interrupting said previously completed short across said auxiliary winding and said capacitor in series relation, means responsive to operation of said controller from its intermediate reverse position into its final reverse position for connecting said auxiliary winding and said capacitor and said control switch in series relation to said source so that said main and auxiliary windings are phased to effect reverse starting of said rotor by said main and auxiliary windings, said relay winding being responsive to a light current traversing it to return said relay contacts into their open position so that reverse running of said rotor is effected by said main winding, means responsive to operation of said controller from either one of its final positions back into the adjacent one of its intermediate positions for disconnecting said auxiliary winding and said capacitor and said control switch in series relation from said source and for completing said short across said auxiliary winding and said capacitor in series relation so as to effect dynamic braking of said rotor, and means responsive to operation of said controller from either one of its intermediate positions back into its off position for disconnecting said main winding and said relay winding in series relation from said source,

9. The control circuit combination set forth in claim 1, wherein said dynamic braking of said rotor instantly arrests rotation thereof so as to prevent overrun of said rotor when said controller is instantly operated from either its forward posi-- tion or its reverse position back into its off position. I

10. The control circuit combination set forth in claim 1, wherein said dynamic braking of said rotor instantly arrests rotation thereof so that said controller may be instantly operated between its forward and reverse positions through its off position to effect a correspondingly instant reversal of the direction of rotation of said rotor.

ALEXANDER J. LEWUS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,380,270 Suhr et al July 10, 1945 2,473,244 Fuller June 14, 1949 

